West German Offenlegungsschrift No. 2,739,367 shows a radial roller bearing assembly having a cage with elastically deformable projections which snap into place behind side surfaces in the bore of the lateral surface of the inner ring formed by grooves or the like. In this manner, the cage is held laterally in place against projections on either the outer or the inner ring. A disadvantage of this type of cage is that it must be made of a relatively soft, deformable material and in many instances, it is necessary to utilize a special manufacturing process which increases the time and expense to manufacture cages of this type.
The aim of the present invention, therefore, is to provide a roller bearing of this general type wherein the cage can be made relatively easy and economically from a relatively hard and stiff material and yet provide the advantages of snap connections between the cage and the retaining element of the outer or inner ring. Cages made of a hard, wear-resistant material are advantageous since they present hard, wear-resistant pocket surfaces against which the rolling elements engage for better accuracy and longer life. The present invention provides a solution to this problem by means of a retaining element which has the necessary flexibility and compressibility characteristics so that it can be snap fitted to the cage and mounted in place in either the inner or outer ring, for example by a press fit. This arrangement facilitates easy assembly of the bearing simply by snapping the projections of the retaining element in the complementary surface of the cage.
The retainer assembly is particularly advantageous in radial roller bearings equipped with conical rollers or cylindrical rollers which are devoid of a retaining flange for the rolling elements on one of the two bearing rings. The retaining projections, therefore, retain the flangeless outer or inner ring provided with a retaining element laterally in place on the cage so that it can be easily pulled out to one side or the other. The flangeless outer or inner ring can be pulled out and removed only by overcoming the bending or compressive elastic forces of the projections of the retaining element.
The cage for a radial roller bearing in accordance with the present invention can be made economically from a rigid, hard material such as sintered materials. The rolling elements are then guided on hard, wear-resistant surfaces of the cage pockets whereby the rolling elements run extremely accurately even when the radial roller bearing is under high load. It has also been found that this arrangement extends the service life of the bearing considerably.
In accordance with still another feature of the present invention, the side surfaces of the cage are formed by two opposing side walls of a ring-shaped groove machined into the lateral surface or the bore surface of the cage.
This facilitates production since milling a ring-shaped groove into the lateral surface of the cage or in the bore surface of the cage is a relatively simple and easy process. In the event that the two side walls of the ring-shaped groove are close to the opposite projections of the retaining element, the inner or outer ring of the unassembled radial roller bearing connected to the retaining element can be pulled apart toward either side. In accordance with another feature of the present invention, the side surfaces of the cage are formed by ledges or shoulders of a circumferential step machined into the bore surface or lateral surface of the cage. By this arrangement, one or both sides of the radial roller bearing are held on a shoulder surface of a step machined into the cage.
In accordance with still another feature of the present invention, the projections of the retaining element are configured to facilitate radial engagement between the shoulder surface of the cage and the axial end surfaces of the rolling elements. By this arrangement, the inner or outer ring of the unassembled radial roller bearing connected to the retaining element is held in place on the cage on both sides.